The present invention relates in general to the alignment of images. More specifically, the present invention relates to a system or method for aligning two or more images (collectively “alignment system” or simply the “system”).
Image processing often requires that two or more images from the same source or from different sources be “registered,” or aligned, so that they can occupy the same image space. Once properly aligned to the same image space, images can then be compared or combined to form a multidimensional image. Image alignment can be useful in many applications. One such possible application is in medical imaging. For example, an image produced by magnetic resonance imaging (“MRI”) and an image produced by computerized axial tomography (“CAT” or “CT”) originate from different sources. When the images are overlaid, information acquired in relation to soft tissue (MRI) and hard tissue (CT) can be combined to more accurately depict an area of the body. The total value of the combined integrated image can exceed the sum of its parts.
Another possible application of image alignment is for quality assurance measurements. For example, radiation oncology often requires image treatment plans to be compared to quality assurance films to determine if the treatment plan is actually being executed. There are also numerous non-medical applications for which image alignment can be very useful.
Several methods are available for image alignment, including automated and manual alignment methods. However, currently available image alignment tools and techniques are inadequate. In many instances, computer automated methods are unsuccessful in aligning images because boundaries are not well defined and images can be poorly focused. Although automated alignment methods perform alignment activities more quickly than existing manual alignment methods, manual alignment methods are often more accurate than automated methods. Thus, manual image alignment methods are often used to make up for deficiencies and inaccuracies of automated alignment methods. However, existing manual alignment systems and methods can be tedious, time consuming, and error prone. It would be desirable for an alignment system to perform in an efficient, accurate, and automated manner.